Evaluation of the biological properties of two experimental calcium silicate sealers: an in vivo study in rats

AIM

To evaluate the biological properties of experimental sealers based on tricalcium silicate and dicalcium silicate, manipulated with polyethylene glycol (CE-1) and with the addition of calcium hypochlorite (CE-2) compared to AH Plus (AHP) and TotalFill BC Sealer (TBC).

METHODOLOGY

The tissue reaction caused by the materials in the subcutaneous tissue of rats was evaluated after implantation of polyethylene tubes filled with the materials at 7, 15, 30 and 60 days. Sections were stained with haematoxylin and eosin (HE) for morphological analysis and to evaluated number of inflammatory cells/mm² (ICs). Sections were used for immunohistochemical detection of interleukin-6 (IL-6) and osteocalcin (OC). The von Kossa method was used to identify calcium precipitation in the capsules. The data were submitted to anova and Tukey's tests, with 5% significance level.

RESULTS

At 7 days, CE-1, CE-2 and AHP had higher numbers of ICs. AHP presented higher immunolabelling for IL-6. After 15 days, regarding IL-6, there was no difference between CE-2 and the control group. At 30 days, AHP exhibited the highest number of IC (P < 0.05) and CE-2 and the control group presented the lowest ICs and IL-6-positive cells. After 60 days, all materials exhibited decreases in ICs. CE-2, TBC and the control had the lowest values (P < 0.05). No significant difference was detected between CE-1 and TBC, and between CE-2 and control considering the immunoexpression of IL-6. In this period, AHP had the greatest number of IC and IL-6 (P < 0.05). In all periods, CE-1, CE-2 and TBC sealers had von Kossa-positive structures and OC-immunolabelled cells. CE-2 had higher number of OC-positive cells than the CE-1 and TBC sealers (P < 0.05), in all periods. OC immunolabelling was not observed in the capsules of AH Plus and the control groups.

CONCLUSIONS

The experimental sealer and its association with calcium hypochlorite, in addition to TotalFill BC Sealer, were biocompatible and had bioactive potential.

Strength and toughness of structural fibres for composite material reinforcement

The characterization of the strength and fracture toughness of three common structural fibres, E-glass, AS4 carbon and Kevlar KM2, is presented in this work. The notched specimens were prepared by means of selective carving of individual fibres by means of the focused ion beam. A straight-fronted edge notch was introduced in a plane perpendicular to the fibre axis, with the relative notch depth being a0/D≈0.1 and the notch radius at the tip approximately 50 nm. The selection of the appropriate beam current during milling operations was performed to avoid to as much as possible any microstructural changes owing to ion impingement. Both notched and un-notched fibres were submitted to uniaxial tensile tests up to failure. The strength of the un-notched fibres was characterized in terms of the Weibull statistics, whereas the residual strength of the notched fibres was used to determine their apparent toughness. To this end, the stress intensity factor of a fronted edge crack was computed by means of the finite-element method for different crack lengths. The experimental results agreed with those reported in the literature for polyacrylonitrile-based carbon fibres obtained by using similar techniques. After mechanical testing, the fracture surface of the fibres was analysed to ascertain the failure mechanisms. It was found that AS4 carbon and E-glass fibres presented the lower toughness with fracture surfaces perpendicular to the fibre axis, emanating from the notch tip. The fractured region of Kevlar KM2 fibres extended along the fibre and showed large permanent deformation, which explains their higher degree of toughness when compared with carbon and glass fibres. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'.

Depressive symptoms and psychosocial aspects of work in bank employees

BACKGROUND

The financial sector has seen an increase in the number of cases of violence and stress, which can result in adverse health outcomes, including depressive symptoms, but studies related to stress at work and depression for these workers are scarce.

AIMS

To investigate the association between exposure to psychosocial work stressors and depressive symptoms in bank employees.

METHODS

A self-administered questionnaire was completed by a sample of bank employees in Pará and Amapá, Brazil. The survey assessed sociodemographic characteristics, mental health (Patient Health Questionnaire-9), Demand-Control-Support and Effort-Reward Imbalance (ERI). Outcomes included two levels of depressive symptoms: major depressive symptoms (MDS) and other forms of depressive symptoms (ODS). Logistic regression models were used to estimate associations between depressive symptoms, the two job stress models and relevant covariates.

RESULTS

Of 2806 eligible subjects, there were 1445 respondents (52% response rate) and the final analyses included 1046 participants. The overall prevalence of depressive symptoms was 32% (MDS = 18%; ODS = 14%), with no statistically significant difference between men and women. High demands, low levels of control and low social support were associated with MDS and/or ODS, adjusted for gender, age and other work-related conditions. High effort/low reward, over-commitment and ERI were also associated with MDS and ODS.

CONCLUSIONS

Psychosocial conditions in banking activity involving high strain, low social support at work, high effort with low reward and over-commitment may represent possible risk factors for depressive symptoms in bank employees.

Military hierarchy, job stress and mental health in peacetime

BACKGROUND

Most studies of mental health in the armed forces focus primarily on post-traumatic stress disorders among military personnel in combat situations.

AIMS

To evaluate the prevalence of common mental disorders (CMD) and job stress, and the association between the two, among military personnel in peacetime. Additionally, it sought to identify occupational subgroups with higher prevalences of CMD.

METHODS

The study participants were 506 military personnel from a Brazilian army directorate in Rio de Janeiro City. CMD were evaluated using the 12-item version General Health Questionnaire. Job characteristics were measured using the effort-reward imbalance (ERI) model and by categories of military rank. Prevalence ratios (PRs) were estimated by Poisson regression to obtain robust (95%) confidence intervals (CIs).

RESULTS

The prevalence of CMD was 33% (95% CI 29-37). After adjusting for age, education, income, lifestyle and other occupational characteristics, ERI was associated with CMD (PR = 2.03; 95% CI 1.3-3.1). Overcommitment proved to be an important component of job stress. Independently of socio-economic, demographic, lifestyle and job stress variables, the rank of lieutenant associated strongly with CMD (PR = 2.02; 95% CI 1.2-4 0.1).

CONCLUSIONS

This study found that job stress among armed forces personnel is associated with CMD. In addition, the specific occupational characteristics of the military environment can lead to a higher prevalence of CMD among those holding the rank of lieutenant.

Association between routine visits for dental checkup and self-perceived oral health in an adult population in Rio de Janeiro: the Pró-Saúde Study

OBJECTIVE

To investigate the association between routine visits for dental checkup and self-perceived oral health.

METHODS

Cross-sectional data from a study of university employees in Rio de Janeiro - The Pró-Saúde Study. Self-perceived oral health and the reported pattern and frequency of visits to the dentist were obtained through a multidimensional self-administered questionnaire.

RESULTS

Data were obtained from 3252 participants. When compared with individuals who reported self-perceived oral health as good ('very good', 'good' or 'fair') individuals who reported self-perceived oral health as bad ('bad' or 'very bad') were significantly more likely to be older, male, less educated, poorer; they also reported more frequently to have lost more teeth and not visiting the dentist for routine dental 'checkup'. Among those who reported visiting for dental checks at least annually, 3% reported bad oral health, as opposed to 15% among those who reported visiting the dentist only when in trouble. Compared with those who reported visiting the dentist at least annually, odds ratio of bad oral health was 3.9 (95% CI, 2.68-5.67) for subjects who reported visiting only when in trouble, 2.6 (95% CI, 1.51-4.62) who reported visiting for dental checks less frequently than once every 2 years, and 1.4 (95% CI, 0.77-2.52) for subjects who reported visiting for dental checks once every 2 years, after controlling for sex, age, education, income and tooth loss.

CONCLUSIONS

Not visiting the dentist for a routine dental check increased the chance of reporting one's own oral health as bad. In any case, the habit of visiting for dental 'checkup, once per year or once every 2 years was associated with nearly all the individuals perceiving his/her oral health positively. However, in order to gather more solid scientific data to guide public policies it is necessary to perform longitudinal studies, especially experiments in different populations focused mainly on the socioeconomic characteristics and dental clinical conditions.

Giardia lamblia: The effects of extracts and fractions from Mentha x piperita Lin. (Lamiaceae) on trophozoites

Giardia lamblia is a parasite that causes giardiasis in humans and other mammals. The common treatment includes different classes of drugs, which were described to produce unpleasant side effects. Mentha x piperita, popularly known as peppermint, is a plant that is frequently used in the popular medicine to treat gastrointestinal symptoms. We examined the effects of crude extracts and fractions from peppermint against G. lamblia (ATCC 30888) on the basis of trophozoite growth, morphology and adherence studies. The methanolic, dichloromethane and hexanic extracts presented IC(50) values of 0.8, 2.5 and 9.0microg/ml after 48h of incubation, respectively. The aqueous extract showed no effect against the trophozoites with an IC(50)>100microg/ml. The aqueous fraction presented a moderate activity with an IC(50) of 45.5microg/ml. The dichloromethane fraction showed the best antigiardial activity, with an IC(50) of 0.75microg/ml after 48h of incubation. The morphological and adhesion assays showed that this fraction caused several alterations on plasma membrane surface of the parasite and inhibited the adhesion of G. lamblia trophozoites. Cytotoxic assays showed that Mentha x piperita presented no toxic effects on the intestinal cell line IEC-6. Our results demonstrated antigiardial activity of Mentha x piperita, indicating its potential value as therapeutic agent against G. lamblia infections.

Susceptibility of Giardia lamblia to Hovenia dulcis extracts

Giardia lamblia is the causative agent of giardiasis, a common parasitic infection of the human and animal digestive tract. Although several drugs have been available to treat this infection, they present unpleasant side effects or cytotoxicity. In order to find a more natural treatment for the disease, we analyzed the effects of the methanolic extract and three fractions obtained from Hovenia dulcis Thunb. (Rhamnaceae) leaves on G. lamblia. Comparing all fractions, dichloromethane was more efficient in reducing Giardia growth. The exposition of G. lamblia to this fraction lead to degenerations in the surface, modifications in the cell shape and alterations in the localization of nuclei. Besides that, the adhesion of G. lamblia was also altered. Experiments revealed that the obtained fraction did not present cytotoxic effects in mammalian cells. In summary, dichloromethane fraction has strong antigiardial effects and could become an important new substance for the treatment of giardiasis.

Biological relevance of E-cadherin-catenin complex proteins in primary epithelial ovarian tumours

This study analysed the biological relevance of E-cadherin, alpha-catenin, beta-catenin and gamma-catenin immunoexpression pattern (reduced vs. preserved phenotype) in epithelial ovarian tumours. Immunohistochemistry was used to evaluate the expression of these proteins in 154 epithelial ovarian tumours, consisting of 17 benign, 33 borderline and 104 malignant tumours. In borderline tumours, the immunoexpression pattern of E-cadherin (p = 0.014) and alpha-catenin (p = 0.030) associated with histological type. In malignant tumours, the immunoexpression pattern of E-cadherin was related with histological type (p = 0.001). The immunoexpression pattern of beta-catenin associated with histological type and tumour differentiation (p = 0.005, p = 0.025, respectively). The preserved phenotype of E-cadherin was most frequently observed in mucinous tumours, whereas reduced E-cadherin was most frequently observed in serous tumours. The preserved phenotype of beta-catenin associated with endometrioid carcinomas, while reduced beta-catenin associated with poorly differentiated serous and clear cell carcinomas. Although the reduced phenotype was the most frequent immunoexpression observed for all proteins of the E-cadherin-catenin complex in epithelial ovarian tumours, only beta-catenin showed a significant difference between benign, borderline and malignant tumours (p = 0.045), since borderline and malignant tumours most frequently showed the reduced phenotype. The immunohistochemical profile of beta-catenin was shown to be of biological relevance: reduced beta-catenin was correlated with loss of tumour differentiation and serous carcinomas that are known to depict aggressive biological behaviour in epithelial ovarian tumours.

Prognostic value of E-cadherin immunoexpression in patients with primary ovarian carcinomas

PURPOSE

To analyse the negative versus positive immunoexpression of E-cadherin in patients with primary ovarian carcinomas, and determine its significance in relation to clinicopathological features, overall and recurrence-free survival (RFS).

PATIENTS AND METHODS

The protein expression of E-cadherin was immunohistochemically evaluated in formalin-fixed, paraffin-embedded samples in 104 patients with primary ovarian carcinomas. The clinicopathological factors studied were age, FIGO staging, histological type, tumour differentiation, the appearance of the ovarian capsule, peritoneal implants and residual tumour after cytoreductive surgery. Overall survival and RFS were evaluated using the Kaplan-Meier method, and multivariate analysis was completed using the Cox regression model.

RESULTS

Of the 104 carcinomas, negative E-cadherin immunoexpression was observed in seven (7%) cases, and positive immunoexpression in 97 (93%). E-cadherin categorised into negative versus positive expression did not associate with any of the established clinicopathological parameters. However, negative E-cadherin expression significantly predicted a poorer overall survival when compared with positive expression (P=0.006). In the multivariate analyses, negative E-cadherin and the presence of residual tumour after cytoreductive surgery were independent prognostic factors for survival (P=0.014 and P=0.034, respectively).

CONCLUSIONS

The presence of residual tumour after primary cytoreductive surgery and negative E-cadherin expression seem to be useful markers in patients with ovarian carcinomas likely to have an unfavourable clinical outcome. The assessment of E-cadherin immunoreactivity may be a useful prognostic indicator in ovarian cancer, complementary to established prognostic factors.

Acute and topic anti-edematogenic fractions isolated from the seeds of Pterodon pubescens

We previously demonstrated that alcoholic extracts from Pterodon pubescens Benth. (Sucupira branca, Leguminosae) seeds exhibit anti-arthritic activity. In the present work we show that the oleaginous extract obtained from P. pubescens seeds (OEP) exhibits acute or topic anti-edematogenic activity when tested in carrageenan-induced paw edema or in croton oil-induced ear edema assays, respectively. Four fractions were obtained from OEP by sequential liquid-liquid extraction. The anti-edematogenic properties were predominant in the hexanic fraction, which was further fractionated by HPLC, yielding three sub-fractions (PF1.1, PF1.2 and PF1.3). PF1.1 and PF1.3 showed potent acute and topic anti-edematogenic activity. The PF1.2 sub-fraction, although not active in the carrageenan assay, exhibited a potent anti-edematogenic activity in the croton oil-induced ear edema. This sub-fraction shows a maximum efficacy similar to indometacin in a lower dose. The PF1.1 sub-fraction presented a complex mixture containing furane diterpene derivatives of vouacapan. PF1.2 consists of a single substance, geranylgeraniol, as determined by GC/MS and NMR, while PF1.3 contains farnesol.

Expression of cell-cycle regulatory proteins and their prognostic value in superficial low-grade urothelial cell carcinoma of the bladder

AIMS

Cell-cycle regulatory proteins are important indicators in determining progression trough the cell-cycle and progression to invasive cancer in patients presenting with superficial bladder cancer. We performed an immunohistochemical study in order to evaluate the prognostic value of the expression of p16, p27, pRb, p53 and Ki-67 in superficial grade I and II papillary urothelial cell carcinoma of the bladder.

METHODS

p16, p27, p53, pRb and Ki-67 immunoexpression was studied in 14 pTa, 35 pT1a and 7 pT1b bladder tumours at presentation and at recurrence of their tumours. The recurrence-free survival and the progression-free survival were analysed according to these regulatory cell-cycle proteins expression.

RESULTS

For survival in univariate analysis a high Ki-67 labelling index was a poor prognostic factor for recurrence-free and progression-free survival (P=0.0014 and P=0.012, respectively). Ki-67 labelling index was also an independent recurrence-free survival prognostic factor (P=0.0005). The p16, p27, p53 and pRb immunoreactivity was not significantly associated with recurrence or progression rate in this group of bladder carcinomas.

CONCLUSIONS

These data suggest that the Ki-67 labelling index can be a reliable marker in predicting recurrence and/or progression in superficial low-grade bladder carcinomas and may be relevant in planning adjuvant therapy.

Characterization of an ecto-phosphatase activity in the human parasite Trichomonas vaginalis

We have characterized phosphatase activity present on the external surface of Trichomonas vaginalis, using intact living parasites. This enzyme hydrolyzes the substrate p-nitrophenylphosphate (p-NPP) at a rate of 134.3+/-14.8 nmol Pi/h per 10(7) cells. This phosphatase activity decreased by increasing the pH from 6.8 to 8.4, a pH range in which cell viability was maintained for at least 1 h. Experiments using classical inhibitors of acid phosphatases, such as ammonium molybdate and sodium fluoride, as well as inhibitors of phosphotyrosine phosphatase, such as sodium orthovanadate, [monoperoxo(picolinato)oxovanadate(V)] (mpV-PIC) and [potassiumbisperoxo(1,10-phenanthroline)oxovanadate(V)] (bpV-PHEN), showed a decrease in this phosphatase activity, with different patterns of inhibition. Cytochemical analysis showed the localization of this enzyme on the parasite surface (cell body and flagellum) and in intracellular vacuoles. Phosphatase reaction products were also observed in exocytosed membrane-bound material.

Bronchodilator activity of Mikania glomerata Sprengel on human bronchi and guinea-pig trachea

The effects of aqueous extracts and hydro-alcoholic extract (HAE), and of a dichloromethane fraction (MG1) obtained from the HAE of Mikania glomerata leaves on isolated respiratory and vascular smooth muscle have been investigated. Aqueousextracts and HAE induced a significant inhibition on the histamine contractions on the isolated guinea-pig trachea. HAE extract induced a concentration-dependent relaxation on guinea-pig trachea pre-contracted with histamine (IC50 0.34 (0.29-0.39) mg mL(-1)), acetylcholine (IC50 0.72 (0.67-0.77) mg mL(-1)) or K+ (IC50 1.41 (1.18-1.64) mg mL(-1)) and on isolated human bronchi precontracted with K+ (IC50 0.34 (0.26-0.42) mg mL(-1)). The dichloromethane fraction induced a concentration dependent relaxation in guinea-pig trachea precontracted with K+ (IC50 0.017 (0.012-0.022) mg mL(-1)). The dichloromethane fraction had also a small vasodilator effect on the isolated mesenteric vascular bed and on the isolated rat aorta, and a significant reduction of the oedema induced by subplantar injections of Bothropsjararaca venom in mice. When tested on plasmid DNA, MG1 did not damage the DNA. Chromatographic analysis showed the presence of 11.4% w/w coumarin in MG1. The results supported the indication of M. glomerata products for the treatment of respiratory diseases where bronchoconstriction is present.

[Social network and social support measures from the Pró-Saúde Study: pre-tests and pilot study]

We describe methodological steps in the selection of questions on social networks and support for a cohort study of 4,030 employees from a public university in Rio de Janeiro. First, group discussions with volunteers were conducted to explore the adequacy of related concepts. Next, questions in the Medical Outcomes Study questionnaire were submitted to standard "forward-" and "back-translation" procedures. The questions were subsequently evaluated through five stages of pre-tests and a pilot study. No question had a proportion of non-response greater than 5%. Pearson correlation coefficients between questions were distant from both zero and unity; correlation between all items and their dimension score was higher than 0.80 in most cases. Finally, Cronbach Alpha coefficients were above 0.70 within each dimension. Results suggest that social networks and support will be adequately measured and will allow for the investigation of their associations with health outcomes in a Brazilian population.

[Reliability of the WPPSI-R test in the evaluation of cognitive development in preschool children]

The WPPSI-R scale (Wechsler Preschool and Primary Scale of Intelligence - Revised) is a psychometric test chosen as the evaluation tool in a study on preschool-age cognitive development in a cohort of very low birth weight (VLBW) premature children from the Fernandes Figueira Institute (IFF), applied by four previously trained psychologists. The objective of this study was to verify inter-observer reliability in the test application. Two types of reliability study design were used: balanced incomplete blocks, to verify agreement in the application of the scale, and crossed design, to verify agreement in scoring of items. We studied 12 preschool children born at IFF (birthweight < 1,500g). The intraclass correlation coefficients (ICC) were: 0.82 (full-scale IQ), 0.89 (verbal IQ), and 0.91 (performance IQ), in the incomplete block design study, and 0.99, 0.98, and 0.99, respectively, in the crossed design study, indicating good reliability. Application of the WPPSI-R scale in the study of cognitive development of VLBW premature children at IFF proved adequate, as shown by these results.

[Analysis of mutations in the BRCA1 gene in patients with cancer of the breast and/or the ovary in Portugal]

Germline mutations in the BRCA1 gene confer an increased susceptibility to breast and ovarian cancer. Approximately 460 distinct mutations were founded scattered throughout the whole gene. However, several mutations were detected repeatedly in individuals of the same ethnic origin. There are no systematic studies concerning mutations in BRCA1 gene in Portugal. The aim of this study is to identify mutations inh this gene in patients with breast and/or ovarian cancer of Portuguese origin. Thirty-three cases of breast cancer and 3 of ovarian cancer were selected according to early age of onset and family history. Mutation screening of this gene was done by Protein Truncation Test (PTT) and Fragment analysis. Two de novo mutations were identified: 1) A frameshift mutation localised in exon 11 of BRCA1, was identify by the two techniques in an ovarian cancer case. Direct sequential revealed a deletion of 4 nucleotides (3444delAAAT); 2) An alteration in intron 18 (IVS 18 + 80delT) was observed in a breast cancer case. This is probably the first description of mutations in a series of patients with breast and/or cancer in the Portuguese population. The mutations identified in this study have not been previously described in other populations according to the Breast Cancer Information Core web site.

A direct interaction between EXT proteins and glycosyltransferases is defective in hereditary multiple exostoses

Hereditary multiple exostoses (HME) is an autosomal dominant condition in which bony outgrowths occur from the juxtaepiphyseal regions of the long bones. In a few percent of cases these exostoses undergo malignant transformation to chondrosarcomas. HME results from mutations in one of two homologous genes, EXT1 and EXT2. These are members of a new gene family that is conserved from Caenorhabditis elegans to higher vertebrates. In humans this family comprises five genes which are most conserved at their C-termini, but they do not contain any discernible functional motifs and their function(s) is unclear. Indirect evidence suggests that EXT proteins are involved in glycosaminoglycan synthesis, act as tumor suppressors and affect hedgehog signaling. One recent study has also reported that these proteins co-purify with glycosyltransferase (GlcA and GlcNAc transferase) activity and on that basis it has been postulated that they are themselves glycosyl-transferases. We performed two-hybrid screens with a fragment of EXT2 from the region that is most highly conserved in the gene family and identified two interacting proteins: the tumor necrosis factor type 1 associated protein and a novel UDP-GalNAc:poly-peptide N -acetylgalactosaminyltransferase. Significantly, both these interactions were abrogated by a disease-causing EXT mutation, indicating that they are important in the etiology of HME. The EXT2-GalNAc-T5 interaction provides the first direct physical link between EXT proteins and known components of glycosamino-glycan synthesis.

[Mental disorders as risk factors for the development of cocaine abuse/dependence: case-control study]

OBJECTIVE

To evaluate the role of psychiatric disorders and alcohol dependence as possible risk factors for cocaine abuse/dependence.

METHODS

The case-control study used the "snowball" technique in order to select untreated cocaine users (cases) and to match sex, age and friendship. Information was gathered using the Composite International Diagnostic Interview (CIDI), and computer diagnosis were generated according to the DSM-III-R criteria. The analysis was performed through the logistic conditional regression.

RESULTS

The study included 208 subjects. The main results showed that having a history of alcohol dependence was independently associated with an increased risk of cocaine abuse/dependence (OR=15,1; 95% CI 3,8-60, 2); no other psychiatric disorder was significantly associated with an increase in this risk after the multivariate analysis. An increased risk of cocaine abuse/dependence was also found for those who related suicide thoughts (OR=3,1; 95% CI 0,91-10,8), suggesting an association between more severe manifestations of depression and cocaine abuse.

CONCLUSIONS

These findings suggest that programs directed towards the treatment and prevention of cocaine abuse must be prepared to address issues related to comorbidity of drug abuse with alcohol and other psychiatric disorders

[Measurement reliability in a study on family violence and severe acute malnutrition]

INTRODUCTION

This study is nested within a research program related to family violence and severe childhood malnutrition. Its aim is to evaluate the reliability of the data collection process in a case-control study. Four components of the main instrument are addressed: (a) CTS (Conflict Tactics Scales) used to measure violence at the family level; (b) CAGE (Cut-down; Annoyed; Guilty & Eye-opener) questionnaire used to gauge suspicion of drinking problems; NSDUQ (Non-student Drugs Use Questionnaire) used to indicate illicit drug consumption; and (d) height/length measurements.

METHOD

Stability (intra-observer or test-retest reliability) and equivalence (inter-observer reliability) were evaluated for the cited components (a), (b) and (c). Information was replicated among the first 50 subjects selected for the underlying case-control study. The Kappa index (k) was used in the analysis. A pseudo-Bayes adjustment was carried out in order to handle estimation problems. Regarding (d), only equivalence was evaluated (n = 73), using the Intraclass Correlation Coefficient as the estimator.

RESULTS

By and large, all components showed acceptable stability and equivalence. Regarding stability, the estimates of k were around 0.70, 0.78 and 0.85, for CTS, CAGE e NSDUQ, respectively. With respect to equivalence, k was 1.0 for CTS and NSDUQ and 0.75 for CAGE. Equivalence for height/length estimated through the ICC was 0.99. Nevertheless, some deviant situations were detected and are further discussed. The results point to an adequate standardization of observers and reflect the good quality of the data collection procedure concerning the main study, encouraging the research team to press forward with greater assurance.

The lack of selection bias in a snowball sampled case-control study on drug abuse

BACKGROUND

Friend controls in matched case-control studies can be a potential source of bias based on the assumption that friends are more likely to share exposure factors. This study evaluates the role of selection bias in a case-control study that used the snowball sampling method based on friendship for the selection of cases and controls.

METHODS

The cases selected fro the study were drug abusers located in the community. Exposure was defined by the presence of at least one psychiatric diagnosis. Psychiatric and drug abuse/dependence diagnoses were made according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R) criteria. Cases and controls were matched on sex, age and friendship. The measurement of selection bias was made through the comparison of the proportion of exposed controls selected by exposed cases (p1) with the proportion of exposed controls selected by unexposed cases (p2). If p1 = p2 then, selection bias should not occur.

RESULTS

The observed distribution of the 185 matched pairs having at least one psychiatric disorder showed a p1 value of 0.52 and a p2 value of 0.51, indicating no selection bias in this study.

CONCLUSIONS

Our findings support the idea that the use of friend controls can produce a valid basis for a case-control study.

Psychiatric and alcohol disorders as risk factors for drug abuse. A case-control study among adults in Rio de Janeiro, Brazil

This study tested the hypothesis that a history of psychiatric and alcohol disorders would affect the risk of developing drug abuse or dependence later in life. This case-control study selected cases and controls using the "snowball" technique in order to obtain cases from this "hidden" population and to match sex, age and friendship. Information was gathered using the Composite International Diagnostic Interview (CIDI), and computer diagnoses were generated according to the DSM-III-R criteria. The study included 370 subjects. Results of the conditional logistic regression analysis showed that having a history of alcohol dependence was independently associated with an increased risk of drug abuse/dependence (OR = 2.6, 95% CI 1.1-6.0) and that this risk was even higher for those whose alcohol dependence occurred in combination with another psychiatric disorder (OR = 4.6, 95% CI 2.1-10.0). An increased risk of drug abuse/dependence was also found for those who were aged 12 years or under when their first psychiatric disorder was manifested (OR = 2.2, 95% CI 1.3-3.7) and among those with two or more psychiatric disorders (OR = 2.5, 95% CI 1.5-4.1). These findings suggest that programmes directed towards the treatment and prevention of drug abuse must be prepared to address psychiatric and alcohol disorders in childhood and adolescence.

Ductal carcinoma in situ of the breast. Histologic categorization and its relationship to ploidy and immunohistochemical expression of hormone receptors, p53, and c-erbB-2 protein

BACKGROUND

Ductal carcinoma in situ (DCIS) of the breast has been diagnosed increasingly since the advent of mammography. However, the natural history of these lesions remains uncertain. Ductal carcinoma in situ of the breast does not represent a single entity but a heterogeneous group with histologic and clinical differences. The histologic subtype of DCIS seems to have an influence on its biologic behavior, but there are few studies correlating subtype with biologic markers.

METHODS

The authors studied a consecutive series of 40 cases of DCIS and after its histologic categorization verified its relationship with ploidy using image analysis and analyzing estrogen receptor (ER), progesterone receptor (PR), p53 and c-erbB-2 expression using immunohistochemistry.

RESULTS

The three groups proposed according to the grade of malignancy were correlated significantly with some of the additional parameters studied, including aneuploidy and c-erbB-2 expression. Aneuploidy was detected in 77.5% of cases of DCIS mainly in high and intermediate grade subtypes (100% and 80% vs. 35.7% in low grade) whereas immunoreactivity for c-erbB-2 was detected in 45% of cases of DCIS mainly in the high grade group. Expression of ER and PR were observed frequently in this study (63.9% and 65.7% respectively), but without correlation with the histologic subtype of DCIS, although we found a somewhat significant association between high grade DCIS and lack of ER, p53 protein expression was detected in 36.8% of these cases, but no relationship between this expression and histologic subtype or grading of DCIS was found.

CONCLUSIONS

These results provide further evidence for the morphologic and biologic heterogeneity of DCIS. Besides histologic classification and nuclear grading, some biologic markers such as aneuploidy and c-erbB-2 expression constitute additional criteria of high grade of malignancy.

An enzyme linked immunosorbent assay (ELISA) that discriminates between Bothrops atrox and Lachesis muta muta venoms

As bites by Bothrops atrox and Lachesis muta muta snakes are frequent in the north of Brazil and elicit similar clinical symptoms, an ELISA assay was developed to identify objectively the circulating antigen in the serum of accidentally bitten patients. Antigens common to the two venoms were removed by immunoaffinity techniques and the 'individual component' of each venom used as immunogen to raise rabbit IgGs. Each of these antibodies specifically recognized one venom, and they were used to set up a sandwich-type ELISA. The specificity of the assay was demonstrated by its capacity to identify correctly the circulating antigen in mice experimentally poisoned with either of the two venoms. The ELISA was further used to identify the circulating antigen in the sera of humans bitten by B. atrox or L. muta muta and to follow the kinetics distribution of antigens in experimentally envenomed mice or accidentally bitten patients. The assay is specific, and could therefore be valuable both to clinicians and to epidemiologists.